Amg63-

so where exactly does the different begin to show from?

it also makes sense if 4matic has less moving parts than Quattro that it should be more efficient it's simple.

gaspam

probably the extra 165 + lbs the awd has vs rwd... at higher speed with increases wind resistant , every incrimental mph is harder to gain and if you're carrying another 165lbs + then each mph is that much harder to gain

kevink2

I know Audi used Torsen center diff's in many of their earlier models, but the Audi RS7 ( that ~compares with the S63 AMG ) actually uses a design similar to the 4MATIC, with a planetary gear with torque bias. There is a good animation 1 min into this video:

"www.youtube.com/watch?v=B7Q-KIKPrgA"

I have a Torsen in the rear of my Rx7, and a few trips to the local road course would turn the synth diff oil black from the heat ... but that's from a lot of cornering with a lot of throttle.

Amg63-

RS7 compares with CLS63/E63 not S63

kevink2

Thanks for the correction Amg63, it's a typo .. I meant E63 AMG, which has been the subject of this thread.

I was answering this reply by gaspam, to my post 41, about whether he thought the E63 AMG 4MATIC had a center diff .
I knew the Mercedes had a center diff, but in a pm, you did not believe me based on this quote from gaspam " its doesnt have a center diff ..." which was taken out of context. I hope it is clear now.

The point of my prior reply should not be lost here. The RS7 QUATTRO awd center diff is NOT a Torsen, it is actually very similar to the E63 4MATIC AMG center diff (perhaps the design patent ran out). So there is little difference in losses there, comparing the two.

BTW, the Torsen does have many parts (actually gears), but it is the high friction (by design) when active that creates relatively high losses in the form of heat

.

Amg63-

yes thank you. Now it's understood that both indeed do have a center diff but the difference is that the 4matic is an open diff while the Quattro has a torsen diff.

It seems like in the reply above you were saying the Quattro system in the rs7 is a very similar design to the 4matic system in the E63. I'm curious to know what it is that makes them so similar?

it seems as of now that the open diff setup on 4matic is at least one difference it has that makes it a more efficient AWD system than the Quattro found in the RS7 as gaspam meant to say earlier. Not sure what other differences they have and would be interesting to get more info on this.

kevink2

See my reply above for all your questions. That reply lagged yours due to my editing. I also answered this question yesterday, post 53.

Amg63-

oh so Quattro doesn't have a torsen diff.

Well then I'm sure they must have some differences we just don't know about right now.

The RS7 with equal modding does show itself to be slower at higher speeds than the E63

perhaps it's not because of the differences in the efficiency of the AWD systems they use, and it's for other reasons.

gaspam

the difference in the RS7 quattro vs older quattro is the newer uses crown gear differential vs torson in the older quattro... the crown gear differential allows variable torque splits, This differential uses wet clutch plates activated by worm gears to progressively shift torque between the axles.... its still more moving parts than 4matic hence why 4matic weights something like 30% less than quattro.... the original point remains as to why our awd system doesnt cause as much driveline loss some other systems... that doesnt necessarily make one better than the other though as many would argue that quattro is best for what it was originally designed for, traction in less than perfect surfaces like hauling *** around a WRC circuit in dirt and snow

kevink2

Now I'm not sure where that audi planetary center diff was used, but I agree on the system you posted for the latest RS7. This is a great video of that latest Audi RS7 awd system, with crowned gears:
https://www.youtube.com/watch?v=_09y...ature=youtu.be

Amg63-

No wonder E63S traps higher and pulls on an equally modded RS7 from a highway roll. All makes sense now as our AWD is permanently fixed torque split while the Quattro is more complex with its variable torque split AWD system.

Amg63-

just wanted to clarify we have noticed the brakes in the E63 in the video against the RWD are the standard grey calipers and not the red calipers which have to come on the S model.

So the video showed a PP rwd vs Non-S AWD. With AWD being same torque level with S it's likely it would never get caught by the RWD from a dig.

PeterUbers

as you and I have discussed I have no idea why a non S variant of the E63 exists

Amg63-

They have a non S for the new w213 e63 as well.

Who knows. Maybe in an effort to grab more marketshare by making it more affordable? Donno bro.

PeterUbers

i guess we live in a world of options why would this be any different

I wonder how many people would not buy the E63 if the only option available was the E63S, so essentially what percentage of overall E63 buyers would not buy the car if they have the spring for a little more car and could only choose the S.

MTV10

How does that make any sense?
With that logic - an RS7 with similar mods should pull the E63... considering the torque split can be switched to a more RWD-bias.....

Amg63-

no because the most it will do is 30/70 which is around the same as 4matic with 33/67 but it has higher drivetrain loss and more weight to deal with.

Makes sense to me.

PeterUbers

+1